Eleazar coffin-



@latten taira gnent-@Hun E LEAZA n COFFIN, or FLIGKSVILLE, PENNSYLVANIA.

Letters Patent No. 72,371, dated .Decemer 17, 1867. I

IMPROVEMENT INVMAGHINES FOR vROUNDING CORNERS'OF SLATE-FRAMES die .rtehnle narran in .there tetters hnelt ma nuttig part rif tlg smic.

TOALL .WHM IT MAY CONCERN:

Beit known that I, ELEAZAR COFFIN, of Flicksvill'e, in the county of Northampton, and State of Pennsyl- Vania, have inventedza new and improved Machine forl Roundingand Ovalling Corners of School-Slate'Frames;

and I do hereby declare the following to be a clear and exact description of the nature thereof, sucient to enable others skilled in the art to which it appertains to fully understand and use the same, reference being p had to the accompanying drawings, making part of the specification, in which- Figure 1 is a side elevation of the device, illustrating my invention.

Figure 2 isa top or plane view thereof.

Figure 3 is acentral'vertical section in the line :z: x, g. 2.

Similar letters of reference indicate correspondingparts in the several figures.

My invention has for its object a device for rounding and ovalling corners of school-slateframes, and consists in a toothed disk or cutter-head, having an annular groove on'its periphery, said cutter-head or disk being mounted on a swinging frame, readily operated, so that when the disk is brought in contact with the corners of the frame, the corners are eut oii', rounded, and m'ade oval simultaneously, by the swinging motion of the diskor cutter-head, which motion is performed or manipulated by any suitable power.

' The mandrel is driven by belts, receiving motion from pulleys on'a swinging frame, in such a manner that the belt is always held taut or stretched, and operates the mandrel at every point that the disk-carrier'assumes in its swinging motion, all in a manner as will behereinafter more fully described.

In the drawings, A represents a frame, constructed of upright, longitudinal, andtransverse pieces a b e.

B is a frame, consisting of uprights d, joined at theirfupper ends by a cross-bar, e. Those uprights, near their lower ends, have perforations, through which passes lloosely themainshaftf, whose bearings are on'the lower longitudinal pieces b of the-frame. Y On the shaftf, between the uprights of the frame D, there is secured by keys, feathers, or otherwisea pulley, g, around which passes a band or belt, h, communicating motion to a similar pulley, j, secured to a shaft, l, which is mounted on the uprights a near their upper ends. A pulley, Z,

is also secured to the shaft 7c, which, with the shaftf, should rest in suitable boxes and-bearings, and have collars or shoulders, or equivalent devices, to preventany lateral play of thc shafts. l K is a cross-belt or band, passing around the pulley Z, and also around a pulley, I, on a mandrel, M. This mandrel turns freely in its bearings in the arms m of a frame, N, consistingof a strip or bar of metal, or'l other material, having its centre bent or bowed so as to allow a space for the pulley L and-the belt K to move without coming in contact with the frame.I

TheA frame N, consisting of the curved or bowed centre, and the arms m, has on the side opposite to the -arms in m', projecting arms or butts n, which are pivoted to arms or butts n', secured to the cross-pieces of the frame at the end opposite to the swinging pulley-frame D. It is evidentthat the frame N will rotate freely on its. hinges orv pivots, and thus carry the 4mandrel .L with it. i To any suitable part of one of the top cross-beams, c, at the end lwhere the pulley-frame D is placed, I secure one end of 'an elastic cord, strap, or spring, 0,'whose other end is attached to the'top cross-piece of the 'pulley-frame B. It will be seen' that the strap O will draw the pulley-frame away from the mandrel N, and

therefore holditaut or stretched the belt or band K. The pulley-frame is drawn outward by the elasticity 'of the strap, but its play in that direction is limited by the cross belt K, which passes around the pulley. l

P represents the cutter-head, having a toothed or serrated periphery, o. A groove, o', is cut in the centre of this'toothed periphery, and continues by preference entirely around the periphery.'4 The cutter-head is 'arranged at the upper 'end of the mandrel M, and is secured thereto by collar,.nut, or any other suitable device.

The swinging framev N,.carrying the mandrel M and cutterhead, is to be operatedand manipulated by thel hand or other. power. For this purpose, in the present case, I employ a key or wrench, R, which is constructed in the form of a.. rank-handle, having a hook at one end instead of the eye, as ordinarily. The hooked end is adapted to catch hold ofthe upper part ofthe frame N, justbelow the arm m ofsaid frame, and the arm of the hook lies under the cutter-head or disk, while the handle projects upwardly alongside the cutterhead,'and above .the frame, so as to 'be readily operated without exposing the hands-of the operator to the cutter-head, as seen invfig. 1.

On the upper'side of the frame A, at the end wherethe cutter-head is arranged, there isvplaced a rest,l iedl or seat, S, having a gauge, T, which is made adjustable, to admit slate-frames of'varyin'g dimensions. The seat S is suitably cut away, leaving a space in which the cutter-head has its play.

The gurages which may be retained in place by set-screws, or any other suitable means, are to be so arranged on the bed or seat S that the corners ofthe slates may be presented to the action ofthe cutter.

y The slates will lie diagonally on the face of the seat, or the seat may be arranged diagonally on the frame and the gauge placed to correspond thereto, to accomplish `the same result.

Other means than the key or wrench'for operating the cutter may be employed. v

The operation is as follows: The slate w is placed on the seat S, theF cutter-bed, by means of the key R, is then turned to the rightvor left to its full extent. The slate is advanced forward to the full limit of the gauge. The cutter-head or diskAis new forced to the side opposite from which it starts, and in this operation describes the arc ot' a circle, at the same time it cuts the corners ofthe slate-frame in a ro'unded'form, and forms'a rounded, bevelled, or chamterededg'e thereon. During this motion of the cutter-head,its mandrel M is rotatechby means ofthe band K passing over the pulley L, and'which receives its power through the medium ofthe pulleys 1,'7', g, and/the main shaftf. As the frame N swings around, the belt K is carried with it, which the swinging frame D allows, but the said belt isltept pefectly taut by the action of the elastic strap or spring O, which draws or pulls thp pulley-frame B away from the mandrel'M', yet yields sutliciently to allow the frame N to describe its arc, butthe belt is always kept sufficiently tight to rotate the mandrel M, irrespective o its position. In lieu' of the elastic strap or spring O, a cord and weight might be substituted, to accomplish the same result as the spring. The pulleys g, j, 7:, maybe arranged on shafts which project on both sides of a single upright shaft, instead of within the frame B.- 'It will be mounted on the main shaft f, and have secured to itsupper end the spring or elastic cord O, but the operationwill be the same as with the frame cZ c. 'The cutter-head or disk, as shown in the'drawings, is in a horizontal position, but it will work equally well when placed vertically, it only `being necessary to arrange the Yworking parts so that the functions of the disk l?, and carrier N, and pulleyframe D, are not destroyed. AMy invention is simple, practical, and useful.v

i Having thus described my invention, what I' claim as new, and desire to secure by Letters Patent, s-'

1. `The pulley-frame B, belt K, and springO, or equivalent, in combination with the mandrel M, mounted on a swinging frame, N, and the operating-key R, or its equivalent, substantially as and for the purpose described.

2. The swinging frame N, carrying the cutter-head P, for the purpose substantially as described. To the above. I have signed my name, this fourteenth day of October, 1867.

' ELEAZAR COFFIN.

Witnesses:

D. McKENNA, WM. A. WIEDERsnn'rM. 

